Milling machine



Aug. 16, 1932. v H. ERNST ET AL 15,872,627

MILLING MACHINE Filed Sept. 23. 19130 2 Sheets-Sheet l "www M flf iV/pif@ Il v @l (sa ,jnvantoz Aug. -16, 1932. H. ERNST ET AL MILLING MACHINE F'iled sept. 2.3. 1930 2 sheets-sheet 2 atto: nu,

Patented Aug. 16, 1932 .UNITED STATES PATENT oFFlcE f -IIANs n-RNsT AND LESTER njNENNINGER, or CINCINNATI, oHIo,-AssIGNons To THE f CINCINNATI MILLING MACHINE COMPANY, OF CINCINNATI, OHIO, A CORPORA- TION OF OHIO MILLING MAGHIN Application Lled September l23, 1 930. Serial No. 483,860.

A `This invention relates to improvementsinV milling Vmachines and has particular' refer-A use has been made in the past of supplemental .i brace members known as overarms which are carried by the rily overlie the arbor being coupled therewith by a suitable support member. VIn

some instances a single overarm and in others a double over-arm has been employed. Analysis of prior art structures, closes the fact that the* doubleoverarm, as hitherto employed, has not ciently rigid brace for the cutter due to the twisting strain exerted thereagainst. 'In the conventional double overarm this twisting strain is sufficient to overcome the clamping force by which the overarms are secured to the pendant movement of the overarms in their `bores with the result that when the `twisting strain ceases, the parts do not return to normal position but on the otherl hand havev received a somewhat permanent lateral set.k This .action is particularly accentuated yif there is looseness in the clamping of either of the overarm members in the column or the clamping of the support thereto.

It is, therefore, the purpose of the present invention to provide a novel and improved structure in which the parts will be `positively interlocked into a unitary rigid bracing member, in which the cross section of the parts will be such Vas to prevent twisting' strain and in which any relative 'twisting or rotating, one part within or about the other, will be entirely prevented and eliminated.

A further object of the invention is the provision of a structure which will relieve the clamping means previously employed from As a result in ther machine column and ordina- Y however, disprovided a suffe" and cause a slight rotational the necessity of resistingthe various twiste ing forces exerted by 'movement of the work :table so that they may serve solely as position.l

controlling membersfthus reducing the tension necessary to be appliedto such members and the liability of stripping of threads or breaking of parts in the attempt to obtain desired rigidity.

Certain employments ofy the inventive principles for accomplishment vof the foregoing results have been illustrated in the accompanying drawings and it will be underin thespeciiic structural details hereinafter Shown and described within the scope of the stood .that we may make anymodiiications appended claim without departing from 'or exceeding the spirit of the invention.

These and other objects are attained by the means described herein and 'disclosedin the accompanying drawings, in which:

Figure .1 1s a perspective view of a standard milling machine having the invention j embodied therein.

Figure 2 is an enlarged sectional view taken online 2-2 of Figure'l.

Figure 3 is a sectional view, similar to j Figure 2, showing a modification of the invention. Figure 4 is a sectional view, similar to Figures 2 and 3, showing another,modification.`

Figure 5 isa sectional view taken on line 5-5 of Figure 4. Figures 6 and of the effect of the distortionalforces involved herein.

In Figure 1 of the drawings is shown a 7 are diagrammatic views standard milling machine comprising theY usual base plate 10 having uprising therefrom a vertical column 11 to which is reciprocably secured the knee 12 for supporting a transversely movable table 13 carried thereby. The usual feed change box 111 and spindle feed control 15 are also carried by the column 11. All of the foregoing details are usual construction and form no part of this invention.

The upper end 16 of the columnv 11 is enlarged for the purpose of providing therein Aa pair of suitable perforations for receiving the overarms, such a's 17 and 18. These perforations are formed complementary to the peripheral contour of the overarms and the t between the parts should be such as to permit longitudinal adjustment of the overarm with respect to the column without any lateral play. Clamp-,means have been provided for rigidly securing the overarms in the column after longitudinal adjustment and may take the form of set screws, such as 19 and 20,

or other suit'a'lale Y known- -means for friction-'l allj7 binding the overarms in the column.

A spindle 21 is journaled in the column beneath the overarms for actuating an arbor? or tool support 22 extending therefrom having a cutter 22 mounted"thereon rI`he overarms 17 and 18 areA provided for the purpose of supporting the tool arbor against. the reaction of the cutter with the workland for this purpose a support member nor pendant 23 having a pair of perforations 24 "and A25, similar in cross section to those inthe, column, is `mounted on the free ends of the overarms. the overarms and' is provided withV a bearing 26`or receiving and yjournaling the voutl board end of thefcutterl arbor 22. A' pair of slots. 27'and 28 intersecting the perfo'ra.h

tions 24 and 25 div-idethe upper part of the pendant into three sections, 29, 30 and 81,

shown` more particularly in Figure 2. AV

transverse bore extends through ythese sec,- tions for receiving asuitable clamping member; such as bolt 32 having a nut 33 threaded ony the `end thereof. From Figure 2 it will be apparent'that upon tightening the nut 'the portions 29 and 31 will be drawn ,toward the intermediate portion 30 thereby frictionally binding the pendant to each overarm.`

From the foregoing ldescription it should In order that .the invention may be more clearly understood reference may be had to Figures 6- and Tin which is diagrammatically.A

shown the effect oftheorces herein involved which tend to distort the arbor supporting structure. In Figure 6 is shown apendant mountedlon the end of a double overarm, the members of which `are cylindrical in cross section.k It has been found that if a force,

such as I3, is applied in the direction' of the arrow, which would be similar in direction to-the reaction set up in the arborA byI ar'cutterinengagement witha workpiece, that thependant will bemoved slightly laterally,

This support depends 'fromk the movement being in the form of rotation substantially about the neutral axis X. The eect of this movement is to cause a slight rotation of the pendant 23 relative to the overarms 17 and 18, which evidently is due to the twisting resistance of the arms being greater than the Yfrictional clamping force between the arms and their sockets. The amount of this movement may be detected bydr'awingah'air line, such as-50-50, in tliep'arts at assembly, as `shown inFigure 'i'. After the application of a laterali force, such asPgthjeInarks will be relatively displaced, as shown in Figure `6. The result of this relative' movementis to effect a lateral set which. prevents the parts from returning to normal Yposition uponycessation of the force P. In other words, the pendantand arms have slipped relative to one another and the pendant has taken a new frictional grip von the .overarms 'It may be possible that instead of the relative movement takingv place between the pendant and the overarms as previously describedfthat the frictional clamping of the overarms in the column may be weaker than in the pendant and v-the relative movement will,rtherefore, take place between` the overn arms and the column. In fact in such a structure. where there are four joints and leach a frictionally clamped one, it is evident that when stress' is put upon the whole structurel theweakest of these joints -willfail and peremit relative movement between the vparts thereof.- l

Due to the nature of the structure wherein the overarms and the pendant must bemaintained in parallelism to preserve the accuracy of 'the machine any `slippage of the joints in such? a structure will disturb the whole alignment-thereof? and prevent the accomplishment of accurate work upon the machine. Furthermore, any relative movement of the nature describedis not `self-compensated forin Aany subsequent movements of the machine and 'can' only be corrected by loosening .all the parts to permit return to normal position and then reclamp them.

Itis, therefore, one of the main objects oi thisinvention-t overcome all of the above diliicultiesbyfproviding an overarm structure in which the'members are so formed as to eliminate any possibility of relative movement between the parts` such as might occur with round overarins, while still maintaining all-the relative adjustments as heretofore.

vOne embodiment of this invention is shown inA Figures 2 and 3 in which the overarms have been `given an irregular cross section by the useof keys 35 and 36 which may be integrally secured to the overarms 17 and 18 respectively in any suitable manner. These keys extend the full length of the overarms and the perforations in the column as well lil as in thefpendant are soformed as to properly receive them. By the application of this inthe arbor support 40.

vention relative rotative movement between the overarms and the column or between the overarms and the pendant support will be positively prevented without depending upon the re istance of a frictional clamp thereby.

causing the cutter reaction to be directly absorbedl by the torsional resistance of the overarms. in other words, if relative movement is positively prevented between the arts forming each connection, the reaction on the cutter arbor will be transmitted to the pendant which acting on one end of the overarms will tend to rotate them in their column socl/:ets but the positive connection'A in the column will prevent this rotation and thereby cause a twisting movement to be set up which will be resisted by the torsional resistance of the overarm. This positive connection also relieves the burden on the clamping bolts 19 and 20, as well as 32, while at the same time permitting adjustment of the overarms in the column, as well as adjustment of the pendant upon the overarms.

ln Figure 3 a modification is disclosed in which the overarms, such as 37, are given a cross section which is other than circular and which serves to prevent movement of the arbor support on the overarms after it has been secured thereto as by the bolt 32. In the use of this modification it is to be understood that the perforations in the column for receiving these overarms will be similar in cross section to those in the pendant whereby longitudinal adjustment of the overarms will be permitted with respect to the column, as well as adjustment of the pendant along the overarms.

A further modification isA disclosed in Figures 4 and 5. In this device circular overarms, such as 38 which have been provided with a flat side, are employed and extend through suitable perforations 39 formed in The arbor support is provided with slots. such as 27 and 28, and a transverse bore for receiving the clamping bolt 32. ln addition to these the arbor support is provided with recesses 41 in which clamp blocks 42 are received. These blocks are provided with aligned perforations 43 through which suitable clamping means, such as the draw bolt 44, extends for drawing the clamp blocks toward one another.

f' These blocks may initiallyhave a circular cross section and then shaped on the upper surface with an angular face 45 which cooperates with the angular faces 46 formed on the overarms 38. In this construction the clamp blocks 42 constitute positive means, which in addition to the friction means, positively secure the arbor support to the overarms and prevents relative movement thereof. Attention is invited to the fact that in l; this modification as in the other the face 46 will extend the full length of the overarms; and the clamping means, such as the blocks 42, will also be provided in the column for securing the overarms therein.

From the foregoing it should now be apparent that each embodiment of this invention provides positive means whereby the arbor support is positively held and prevented from relative movement with respect to the overarms and that'the overarms are positivelyy held against relative movement with respect to the column and that these results have been obtained without interfering with the relative adjustment of the overarms with respect to the column or of the pendant with respect to the overarms.

That whichv is claimed is:

ln a millingmachine the combination of a support, a pair of overarms extending through and beyond the support, an arbor extending from the support and positioned below the overarms, an arbor support receiving the free ends of the overarms and arbor, the arbor support having slots therein in alignment with the overarms, means extending through the arbor support for drawing the sections thereof toward one another for frictionally binding the overarms in lthe arbor support, the arbor support being further provided with recesses. below the overarms, clamp blocks received in the recesses having angular faces formed thereon, angular faces formed on the overarms cooperating with the angular faces on the clamp blocks, the arbor support and clamp blocks having bores formed therein in axial alignment, and means extending through the aligned bores for drawing the clamp blocks toward one another and for causing a locking engagement of the angular faces on the wedge blocks and overarms for positively llocking the arbor support in position on the overarms.

in testimony whereof we affix our signatures.

HANS ERNST. LESTER F. NENNINGER. 

